Lubricating device for lockstitch sewing machine loopers



y 1970 H. BERNEZWASSER 3,513,794

LUBRICATING DEVICE FOR LOCKSTITCH SEWING MACHINE L( )OPERS Filed Aug. 27, 1968 B Fig. 1

@4 1 I? 1 WIN l//// IN VENT OR 66x6 r eu/ossf United States Patent 3,513,794 LUBRICATING DEVICE FOR LOCKSTITCH SEWING MACHINE LOOPERS Horst Bernewasser, Steinhagen, near Bielefeld, Germany, assignor to Kochs Adlernahmaschinen Werke AG, Bielefeld, Germany Filed Aug. 27, 1968, Ser. No. 755,620

Claims priority, application Germany, Mar. 29, 1968,

K 59,614 Int. Cl. D05b 71/00 US. Cl. 112-256 3 Claims ABSTRACT OF THE DISCLOSURE A lubricating device for lockstitch sewing machine loopers wherein the raceway receiving the bobbin case holder is supplied with an adjustable quantity of lubricant as a function of the speed of the looper. A projection within an oil chamber and rotating with the looper causes a vacuum for the suction adsorption of lubricant from an oil reservoir and its transfer to the raceway.

BACKGROUND OF THE INVENTION The present invention relates to a device used in lockstitch sewing machines for feeding lubricant from an oil reservoir in the sewing machine, into an oil chamber rotating with the looper, by means of a wick disposed in a conduit and immersed in the oil reservoir, and through a duct to the raceway of the rotating looper.

There are already known devices for lubricating the raceway of rotary loopers, in which the lubricant reaches the points to be lubricated by capillary action or gravity or by means of a pump. Lubricating means of the first and second types are disadvantageous in that the supply of oil cannot be interrupted when the sewing machine is not in operation. The use of a pump requires a fine adjustment of valves to provide an accurate dosing of the oil flowing to the raceway of the looper. Moreover the use of a pump and valves is expensive.

It is an object of the invention to provide a lubricating device for loopers, which is simple and dependable in operation.

It is a further object of the invention to provide a lubricating device for the looper of a lockstitch sewing machine which will deliver a quantity of lubricant depending upon rotation of the looper.

It is a further object of the invention to provide lubricating device means which will supply, when needed, an adjustable quantity of lubricant corresponding to the actual consumption and which will interrupt the flow of lubricant when the sewing machine is stopped. Another object of the invention is to provide lubrication device means which requires fewer parts and is more economical than conventional lockstitch looper lubricating devices.

Finally, it is an object of the invention to provide a lubricating device for loopers which can be installed in existing machines with relative ease.

SUMMARY According to the invention these objects are achieved in lockstitch sewing machines by means of a lubricating device for the looper, in which the lubricant flows through a wick to an oil chamber of the looper and by means of a supply duct leading to the raceway of the looper. The oil chamber is provided with an inner disk-shaped wall and an outwardly extending conical wall defining an annular open space around the looper shaft. The looper has at least one projection on the inner disk-shaped wall, spaced from the looper sha-ft within the area of the wick, projecting with its one end into the oil chamber and said end being spaced from the projection.

3,513,794 Patented May 26, 1970 In a preferred embodiment of the invention, the projection may consist of a trunnion set screw threaded into the inner disk-shaped wall spaced from the looper shaft within the area of the wick, the set screw being spacially adjustable with relation to the wick.

The oil reservoir which is mounted below the bedplate, is carried by a bushing secured in a lug depending from the bedplate. The bushing includes a bearing for the looper shaft and a bore for receiving the conduit for the wick.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation, in longitudinal section, through a part of the bedplate, the looper and the oil reservoir of the preferred embodiment of the lubricating device, and

FIG. 2 is a sectional view of a modified device for lubricating the looper of a lockstitch sewing machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotary looper 2, arranged below the bedplate 1, is secured on the left end of the looper shaft 3. The looper 2 formed with a basket is provided with a raceway 4 for receiving a bobbin case holder 5- having a peripheral bearing rib 6. The bobbin case holder 5 is prevented from rotation with the looper 2 by means of a stop-lug 7 in known manner.

Arranged in the looper 2 is an oil chamber 8 having an inner disk-shaped wall 12 and an outwardly extending conical wall 8', defining an annular open space around the looper shaft 3. A conduit 9 having a wick 10, projects with its one end into the oil chamber 8 and with its other end into an oil reservoir 11 mounted below the bedplate 1. The oil reservoir 11 is carried by a bushing 17 which is secured in a lug 18 depending from the bed plate 1. The bushing 17 comprises a bearing 19 for the looper shaft 3 and a bore 20 for receiving the conduit 9.

The inner disk-shaped wall 12 of the looper 2 (FIG. 2) is formed with a projection 13 arranged spacedly of the looper shaft 3 within the area of the conduit 9 and the wick 10. During the rotation of the looper 2, the projection 13 passes near the wick 1-0'. The rotation of the looper creates a more or less strong air current, depending on the speed of rotation. This air current thereby effects a vacuum causing a suction adsorption of a certain quantity of oil from the oil reservoir 11 through the wick 10. When the quantity of oil is large enough, it is taken along by the projection 13' and as a result of the eifected centrifugal force it is thrown against the conical wall 8'. The lubricant reaches the raceway 4 of the looper 2 through a supply duct 14.

The continually adsorbed quantity of lubricant depends on the speed of rotation of the looper 2 and on the air gap A between the projection 13 and the end of the wick 10 in the conduit. The smaller the air gap A, the larger the adsorbed quantity of lubricant.

As can be seen from the preferred embodiment of this invention, shown in FIG. 1, the projection 13 (FIG. 2) can be replaced by a trunnion set screw 16, received in a taphole in the looper 2 and provided with a slit for a screw driver. By varying the distance A between the trunnion 15 and the end of the wick 10, the quantity of oil to be adsorbed can be easily regulated. The smaller the distance A the greater is the quantity of the lubricant which reaches the raceway 4, and vice versa.

Instead of only one projection 13- or one trunnion set screw 16, there can obviously bep rovided two or more projections or trunnions to increase the effect.

Although the invention has been described in its preferred forms, it is understood that the present disclosure of the preferred forms has been made by way of sample only and that numerous changes in the details of construction and the combination and arrangement of part may be resorted to without departing from the spirit and the scope of the invention.

What I claim is:

1. In a lockstitch sewing machine having a horizontally disposed bedplate, a horizontally rotatable looper shaft disposed substantially parallel with said bedplate, a looper carried by the left end of said shaft and provided with a raceway, a bobbin housing journaled in said raceway, an oil chamber having an inner disk-shaped Wall and an outwardly extending conical wall defining an annular open space about said looper shaft, a supply duct extending parallel to said shaft from said oil chamber through said disk-shaped wall into said raceway, an oil reservoir mounted below said bedplate, a conduit projecting with its one end into said oil chamber and with its other end into said reservoir, and a wick in said conduit, said looper having at least one projection arranged on said inner diskshaped wall and spaced from said looper shaft within the area of said wick, said projection being closely spaced from said one end of the wick.

2. In a lockstitch sewing machine as claimed in claim 1, wherein said projection consists of a trunnion set screw threaded into said inner disk-shaped wall and spaced from said looper shaft, said trunnion screw being specially adjustable with relation to said one end of the wick.

3. In a lockstitch sewing machine of claim 1, a lug depending from said bedplate, a bushing secured to said lug, said bushing being provided with a bearing for said looper shaft and a bore for receiving said conduit.

References Cited UNITED STATES PATENTS 2,201,803 5/1940 Todd 184-64 XR 2,381,685 8/1945 Parry 112256 2,762,325 9/1956 Hale et a1. l12256 MERVIN STEIN, Primary Examiner G. H. KRIZMANICH, Assistant Examiner 

